Protective device for a controlling system of a sewage pump

ABSTRACT

A protective device for a controlling system of a sewage pump has a protective circuit to protect a start capacitor and to avoid the start capacitor from burnout when an overload is occurred by actuating power source (ON status) or when a transient voltage is occurred by malfunction of a controlling circuit. Therefore, the start capacitor is certainly protected and significantly improved in lifespan.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a protective device for a controlling system of a sewage pump, and more particularly to a protective device that controls pump operation and has a protective circuit protecting a start capacitor in the controlling system to avoid the start capacitor from burnout when an overload is occurred by actuating power source (ON status) or when a transient voltage is occurred by malfunction of a controlling circuit.

2. Description of Related Art

A conventional sewage pump system in accordance with the prior art has an operational controlling circuit system for controlling the operation of a sewage pump. The operational controlling circuit system has a start capacitor connected with a run capacitor in parallel connection and with a switch in series connection and further connected with an actuating coil and an operating coil to perform a combined circuit. In the operational controlling circuit system, the actuating coil and the operating coil drive the sewage pump to function when the electrical power is supplied. Because the switch is the essential element to control the sewage pump to work or to stop, its contact is always changed between a normal closed (N.C.) status and a normal open (N.O.) status. Moreover, its contact has carbon-deposition or oxidation incurred by electric sparkles of large current. Therefore, the contact can not successfully disengage and is kept at the normal closed (N.C.) status that makes the start capacitor to electrically connect the power source. When the start capacitor is kept to be charged, it will burnout sooner or later.

According to above description, the conventional sewage pump system still has some drawbacks in use.

SUMMARY OF THE INVENTION

A main objective of the present invention is to provide a protective device for a controlling system of a sewage pump, wherein the protective device protects a start capacitor from keeping discharge and burnout when a switch is abnormally suspended at a normal closed (N.C.) status.

To achieve the foregoing objective, the protective device for a controlling system of a sewage pump with a start capacitor and a run capacitor, the protective device comprising a protective circuit composed of a centrifugal switch adapted to mount on an output shaft of the sewage pump and providing a protective efficiency by cutting power to avoid the start capacitor in the sewage pump from burnout.

By having the protective circuit, the start capacitor is protected from burnout to have extended lifespan.

Further benefits and advantages of the present invention will become apparent after a careful reading of the detailed description with appropriate reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a sewage pump system with a protective device in accordance with the present invention; and

FIG. 2 is a schematic circuit diagram for the sewage pump system with the protective device in the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A protective device for a controlling system of a sewage pump in accordance with the present invention has a protective circuit to protect a start capacitor and to avoid the start capacitor from burnout when an overload is occurred by actuating power source (ON status) or when a transient voltage is occurred by malfunction of a controlling circuit. Therefore, the start capacitor is certainly protected and significantly improved in lifespan.

The protective device for a controlling system of a sewage pump is applied to an operation-controlling circuit system 2 to drive a sewage pump 1 as shown in FIG. 1, wherein the operation-controlling circuit system 2 as shown in FIG. 2 has a start capacitor 21 and a run capacitor 22 connected in parallel connection. The start capacitor 21 connects a centrifugal switch 3 in series connection and adapts to connect to an actuating coil 11 and an operating coil 12 of the sewage pump 1 to form a combined circuit. Specifically, the start capacitor 21 and the run capacitor 22 are operationally and respectively connected to the actuating coil 11 and the operating coil 12 at two ends of their parallel connection to achieve the combined circuit for the operation of the sewage pump. In the operation-controlling circuit system 2, the actuating coil 11 and the operating coil 12 start to make the sewage pump operate when the power is supplied. Meanwhile, the centrifugal switch 3 adapted to mount on a central shaft 4 of the sewage pump 1 changes its contact from the normal closed (N.C.) status to the normal open (N.O.) status by the centrifugal force from rotation of the central shaft 4. Thereby, the start capacitor 21 is electrically isolated from the power source because of the broken circuit. Then, the start capacitor 21 stops the discharging movement and the functioning status of charging or discharging to protect itself from burnout during long-term operation.

According to above description, the protective device for a controlling system of a sewage pump has the following advantage that:

the centrifugal switch in the protective device is a mechanical centrifugal switch and changes it contact from the normal closed (N.C.) status to the normal open (N.O.) status by the centrifugal force from rotation of the central shaft 4. Thereby, the start capacitor 21 is electrically isolated from the power source because of the broken circuit. Then, the start capacitor 21 stops the discharging movement and the functioning status of charging or discharging to protect itself from burnout during long-term operation.

Although this invention has been described in its preferred form with a certain degree of particularity, it is understood that the present invention of the preferred form has been made only by way of example and that numerous changes in the details of construction and the combination and arrangement of parts any be resorted to without departing from the spirit and scope of the invention. 

1. A protective device for a controlling system of a sewage pump with a start capacitor and a run capacitor, the protective device comprising a protective circuit composed of a centrifugal switch adapted to mount on an output shaft of the sewage pump and providing a protective efficiency by cutting power to avoid the start capacitor in the sewage pump from burnout.
 2. The protective device as claimed in claim 1, wherein one end of the centrifugal switch is adapted to connect to the start capacitor in series connection; another end of the centrifugal switch is adapted to connect to the run capacitor in parallel connection; wherein, the start capacitor and the run capacitor are operationally and respectively in parallel connection and are connected to an actuating coil and an operating coil at two ends of the parallel connection to achieve a combined circuit for the operation of the sewage pump. 